It's Complicated: Pacific Ocean Impacts Global Warming by Lowering Climate Temperatures

The Pacific Ocean may be having a huge impact on global warming. It turns out that equatorial cooling in the ocean is actually offsetting rises in temperatures. A view of the Pacific Ocean along the bluffs of Torrey Pines Reserves near San Diego, CA. (Photo : Flickr.com/Jim Epter)

Catherine Griffin

September 4, 2013

The Pacific Ocean may be having a huge impact on global warming. It turns out that equatorial cooling in the ocean is actually offsetting rises in temperatures. This finding could have major implications for the future if ocean waters begin to warm once more.

Global mean temperatures have been flat for the last 15 years, despite an increase of heat-trapping greenhouse gases. Needless to say, this seems like a contradiction. Yet scientists have now discovered what has caused this particular halt in rising temperatures by creating a new model.

"Climate models consider anthropogenic forcings like greenhouse gases and tiny atmospheric particles known as aerosols, but they cannot study a specific climate event like the current hiatus," said Yu Kosaka, a Scripps climate scientist, in a news release. "We devised a new method for climate models to take equatorial Pacific Ocean temperatures as an additional input. Then amazingly our model can simulate the hiatus well."

During the northern winter season, there's a slight cooling trend in global temperature. In summer, the Pacific's grip on the Northern Hemisphere loosens and the increasing greenhouse gases take more of an effect, warming temperatures. This can cause massive heat waves and Arctic sea ice retreat.

Natural climate cycles govern ocean cooling. Yet when this cycle reverses and the Pacific waters begin to warm again, the increase in global temperature will resume quickly. In fact, we could see some major changes to our world's temperatures. Currently, researchers aren't sure exactly how long this cooling phase will last and predicting Pacific conditions more than a year in advance is impossible.

"That speaks to the challenge in predicting climate for the next few years," said Shang-Ping Xie, one of the researchers, in a news release. "We don't know precisely when we're going to come out of [the hiatus] but we know that over the timescale of several decades, climate will continue to warm as we pump more greenhouse gases into the atmosphere."

The findings reveal exactly how important it is to take into account various environmental impacts when it comes to predicting temperature. In addition, it shows exactly how the current hiatus has come about and has enormous implications for future warming conditions.

The findings are published in the journal Nature.